The present invention relates to check valves for incorporation within a passageway to allow fluid flow in only one direction therethrough, and more particularly, to check valves incorporated in the walls of game balls and the like for the inflation thereof.
Certain types of game balls such as basketballs and volleyballs, are made with relatively thin rubber shells which are inflated by air pressure to several pounds per square inch, so as to give them a lively bounce and action that makes for a fast game. Typically, a small unitary check valve is disposed within the wall of the game ball for the insertion of initial pressurizing air into the interior of the game ball. During the course of time, the pressurizing air leaks slowly through the rubber by diffusion through the molecular spaces in the rubber and through the pressurizing check valve due to the construction method thereof and momentary opening thereof due to shocks induced in the playing of the game played with the game ball.
Other types of game balls, such as tennis balls and racquet balls, are also made with relatively thin rubber shells which are gas pressurized at manufacture. In the prior art, tennis balls and racquet balls have not been provided with pressurizing valves since the check valves available in the teaching of the prior art were incapable of withstanding the shocks attendant the game so as to prevent the small volume of pressurized gas contained therein from leaking out. Thus, in tennis balls and racquet balls, the amount of leakage has primarily been a function of the time that has elapsed since the pressurized can the ball was shipped in was opened. Thus, a brand new tennis ball or racquet ball that has been used only once or twice and then set aside for a few weeks may be found to be considerably softened and somewhat dead when used again in play. Inasmuch as tennis balls are fairly expensive, the cost can become an objectionable item when a ball goes dead after being used only a few times.
Another shortcoming of tennis balls is that they rarely have the exact same bounce. Sometimes, in fact, a brand new ball will have so little bounce that it cannot be used at all. One measure of "bounce" is that determined by dropping the ball from a given height. Ideally, all brand new balls dropped from a given height should bounce up to the same level. This is seldom the case. As a result, when players use one ball after another, the action of each ball becomes unpredictable. Under such conditions, the players may have difficulty in controlling their shots. This is particularly important in tournament type play wherein the same advantage should be had by all players at all times.
In my U.S. Pat. No. 4,012,041, a method is disclosed wherein tennis balls and racquet balls can be provided with a check valve for the maintenance of such balls in identical playing condition to preselected standards. Such a method, of course, requires a check valve which will be able to withstand the rigors of the tennis or racquet ball game without attendant loss of pressure contrary to the ability of prior art game ball check valves.
Such problems also exist in other apparatus employing check valves used in pressurization processes or for the control of the unitary flow of fluid through a passageway. For example, the typical automobile tire is provided with a complex check valve employing springs, threaded metal parts, and elastomeric seals in order to provide a repressurizable sealed passageway which will not rapidly allow the passage of the internal pressurizing air under the high shock conditions attendant driving the automobile tire under typical traffic and road conditions.
Wherefore, it is the primary object of the present invention to provide a new and improved check valve for an inflatable game ball, whereby the ball can be initially inflated or repressurized as needed to any desired pressure so as to maintain its liveliness, or bounce, at a consistently high level, regardless of the time that has elapsed since the ball was first put into use.
Another important object of the invention is to provide a unique form of check valve that can be used with any inflatable article, such as an automobile tire, for example, which is simple and inexpensive to manufacture, reliable, and trouble-free.
It is yet another object of the present invention to provide a check valve that can be used in the control of fluid flow through a passageway which tends to increasingly seal the passageway in the presence of increased pressures tending to allow fluid flow in the non-desired direction.